Voltage generators, such as generation circuits, are used in a variety of applications where constant and/or variable voltages are utilized, such as might be used in a memory device, for example. Memory devices are typically provided as internal, semiconductor, integrated circuits in computers or other electronic devices. There are many different types of memory including random-access memory (RAM), read only memory (ROM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and flash memory.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Non-volatile memory is memory that can retain its stored data for some extended period without the application of power. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the cells, through programming (which is sometimes referred to as writing) of charge storage structures (e.g., floating gates or charge traps) or other physical phenomena (e.g., phase change or polarization), determine the data state of each cell. Common uses for flash memory and other non-volatile memory include personal computers, personal digital assistants (PDAs), digital cameras, digital media players, digital recorders, games, appliances, vehicles, wireless devices, mobile telephones and removable memory modules, and the uses for non-volatile memory continue to expand.
Flash memory devices typically require voltage generators in order to support various memory device operations, such as programming, reading, verifying and erase operations, for example. Flash memory devices comprise semiconductor components which can be affected by variations in the operating temperature of the device. The resulting effect on the operating characteristics of the memory device may in various circumstances lead to corruption of data retrieved from the memory device, such as during a read or verify operation performed on the memory device, for example.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for voltage generators which adjust (e.g., compensate) for potential variations in operating characteristics of a memory device, such as due to changes in the operating temperature of the memory device, for example.